i did not realize that soybean, safflower and avocado oils have very high smoke points. the oil that is not on the list but is getting a lot of attention is rice bran oil - smoke point 490 f /254 c. i use it to coat barbecue grills before grilling and it does a great job in preventing the meat from sticking to the grill

However, another source for similar information (admittedly less objective by nature) is Spectrum Organic's 1-2-3 guide to cooking oils. They offer a bunch of different oils at reasonable prices and their guide is written for their oils, so at least you know what product they refer to. (NOW oils seems to process their products in a similar fashion, FWIW).

It does not cover rice bran oil, of which I bought a 16oz. bottle for $5 and used for a bo luc lac yesterday evening. It worked well at high heat, so there are some oils worth exploring which are not in the 1-2-3 guide. But the guide is more specific and less confusing than Mr. Chu's (great!) table, above.

Lots of people keen on their cooking. I have taken to using beef dripping or lard as approriate when cooking meats, a much more suitable flavour, of course.

What brought me to the site however is my seach for a heat transfer oil, anybody know some flash and fire points of high temperature oils. also why do manufactures bother to make synthetic ois for heat transfer when these veg oils have such higher smoke/flash points?

Does anyone have any recommendations for an oil to use in seasoning cast iron cookware? Most of what I have always been told to use was either vegetable shortening or liquefied bacon fat. I'm about to re-season mine and wonder if a something with a higher smoke point would last any longer or if any are more resistant to acid attack (such as tomato based sauces).

I like to cook with Grapeseed oil. It has a high smoke point-around 420F and has VERY little taste. To season cast iron with it, you need to coat the pan well and "cook" the pan above its smoke point so the oil carbonizes. I'd bake it at 450F in an oven for an hour. When you take the pan out, let it cool and it must be smooth and NOT tacky to the touch. If the pan is sticky, all you have is a dirty pan. Put it back and cook it longer or if your oven never got to 450, check the temperature with an oven thermometer and cook it again.

I poured some grapeseed oil inside the pan, then used a paper towel to spread it around the rest of the pan (bottom, handle, and sides), baked at 400 F for 45 minutes, spread another layer on and baked at 450 for 45 minutes and 500 for 45 minutes (since I've seen the smokepoint of the oil varied here between 420-485 F).

What turned out was mostly perfect. The inside of the pan was as smooth as could be (not gummy anywhere) but also appeared somewhat striated. To explain, it looked as if some of it had carbonized at different rates in little pools or bubbles, but being that I put it on the rack upside down, this could not be the case. The rims of the pan, on the other hand, appeared almost powder coated in some spots and had raised areas of carbonization. These were easily scraped off with a thumbnail and revealed what looks like *rust* on the underside of these raised areas. This, too, came off with a fingernail, but it certainly looks a lot like rust.

I have decided that I will put more oil on the inside and the rim and try this again at no more than 450 F.

When reading Michael's comments on Polyunsaturated fat, I am unsure of how he comes to the conclusion they are bad and should be avoided. I am studying nutrition and I have learned they are good fats- in fact, the best fats. He is right in saying too much Omega-6 fatty acids are bad, and we do get enough or too much in our diets, but it is the ratio of Omega-3 to Omega-6 fatty acids that is important. Omega-3's are polyunsaturated and are the most beneficial to your health when you are getting Omega-6's. Michael says a diet high in polyunsaturates should be resricted, and I don't know how he can come to that conclusion. When he says, "And in my fats article I note that avoidance of saturated fats may not be a healthful choice. In fact, high consumption of polyunsaturates should be avoided" he is giving people false information. Saturated fats are much worse for blood cholesterol levels and overall heart health, and I don't think these claims that 'polyunsaturated are bad' is accurate. This is misleading people, and they need to know the full story- they need a ratio between 2:1 and 4:1 (Omega-6 to Omega-3) for optimal health benefits.
As well, do people really heat an oil past 100 degrees celsius? Most oils high in polyunsaturated fat won't be forming trans fats because most people don't heat their oil to a very high temperature. If they are using it for deep frying, they can use a high stability variety. This is by far the better alternative to saturated fats.

Michael says a diet high in polyunsaturates should be resricted, and I don't know how he can come to that conclusion. When he says, "And in my fats article I note that avoidance of saturated fats may not be a healthful choice. In fact, high consumption of polyunsaturates should be avoided" he is giving people false information. Saturated fats are much worse for blood cholesterol levels and overall heart health, and I don't think these claims that 'polyunsaturated are bad' is accurate. This is misleading people, and they need to know the full story- they need a ratio between 2:1 and 4:1 (Omega-6 to Omega-3) for optimal health benefits.

There is merit to what you say, but over the last couple years I've been reading more and more about the research conducted in this area and am leaning towards agreeing with Michael and his views on fats. It is true that a healthy ratio of n-6 and n-3 fatty acids should be maintained, but in the Western world we consume so much more n-6 than n-3 it's obscene (ratios of 6:1 or 10:1 are not uncommon). He doesn't say (I wouldn't back him up on this if he did) to cut out poly, just to limit consumption. This is because poly has a tendency to break down easily (not just through overheating, repeated use, but also in the stomach during digestion) and release free radicals. It's not an issue of poly turning into trans, but an issue of cancer causing agents being released into the body. Once way to combat this is to add an oil stabilizer such as acetic acid to your oil, another is to eat a lot of antioxidants. (Or, as Michael suggests, simply focus more on monounsaturated and saturated fats which do not have this problem.) Avoiding trans should drastically reduce your chances of heart disease; reducing consumption of poly should reduce your chances of certian types of cancer.

Also, on a different subject, Michael may be right about saturated fats. Experiments have to be performed again on saturated fats (not a mixutre of trans and sat fats as was previously done) to demonstrate if they are harmful to the body. The whole cholesterol consumption thing is bullshit as well (apologies for the language Michael)

Anonymous wrote:

As well, do people really heat an oil past 100 degrees celsius?

Do you cook anything with oil? The pan barely sizzles with water when you heat oil to 100...

I'm not disputing the fact that too much Omega-6 is bad, and we already get too much in our diets. I completely agree with that.
The major issue I have is over the saturated fat. Saturated fat DOES raise cholesterol levels and clog arteries - unless I'm wasting my tuition studying nutrition. The american heart association has a section on trans fats you may want to look over.
http://www.americanheart.org/presenter.jhtml?identifier=3045790

In which they conclude "This study shows that in a group of healthy young men with an average plasma cholesterol concentration of 4.2 mmol/l (163 mg/dl) when consuming a diet in which fat supplies only about 30% of energy requirements, removal of saturated fatty acid leads to a reduction in their plasma cholesterol concentration."

This article, in my opinion, is unbiased and talks about some of the concerns you presented on omega-3's, however, it also seems to me that it supports Omega-3's as a better choice. There are so many factors you have to look at before you can make claims, I just don't agree with presenting people with misleading ideas that only present one side of the story.

But, hey, I guess a degree in computer engineering gives you the authority to influence what people eat.

If there is a peer-reviewed, scientific article published by a professional that says saturated fat is good and should be consumed instead of polyunsaturated fat, then I will take it all back.

Q. I was told that canola oil changed to trans fatty acids when it is heated, as in cooking. Is this true?

The phenomenon that occurs is vegetable oils is known as lipid oxidation or rancidity. Lipid oxidation involves the breakdown of fatty acids in the oil to produce secondary compounds that reduce the nutritive value and produce off-flavors and odors. Only under the most severe frying circumstances will the fatty acid composition of an oil be significantly altered. It is very rare for either the consumer or food processor to fry with an oil under the conditions necessary for the formation of trans fatty acids. The production of trans fatty acids to any significant degree in an oil without the use of hydrogenation is extremely rare. It is important to note that foods prepared in rancid fats are likely to be inedible due to the development of off-flavor and odors as well as deterioration in the appearance of the oil. The oil would likely be discarded before it could be subjected to the levels of light, heat and oxygen necessary to produce trans fatty acids